Effervescent composition

ABSTRACT

A stable cleansing composition, for example, a powder for dentures, which dissolves at a favorable rate to form a clear, non-foamy oxygen-effervescent solution and which comprises certain proportions of sodium perborate monohydrate, lithium hypochlorite, and phosphate salts.

United States Patent [191 Kohlhepp et a1.

[ Feb. 19, 1974 EFFERVESCENT COMPOSITION [75] Inventors: Frederick F. Kohlhepp, Princeton Junction; Herman E. Jass, Princeton, both of NJ.

[73] Assignee: Carter-Wallace, Inc., New York,

[22] Filed: July 23, 1971 [211 Appl. No.: 165,395

[52] U.S. Cl 252/99, 252/103, 252/105, 252/186, 8/109, 424/53, 424/130, 424/149 [51] Int. Cl ..Cl1d 7/54 [58] Field of Search 252/99, 186, 103-105, 252/187; 8/109; 424/53, 130, 149

[56] References Cited UNITED STATES PATENTS 3,696,041 10/1972 Gray 252/99 12/1972 Gray 252/99 X 2/1972 Fitzgerald, Jr. 252/99 X Primary Examiner-Mayer Weinblatt Attorney, Agent, or Firml(evin B. Clarke [57] ABSTRACT 10 Claims, N0 Drawings 1 EFFERVESCENT COMPOSITION BACKGROUND OF THE INVENTION The present invention lies in the field of cleansing compositions. More specifically, the invention involvesa powder composition which can be placed in water wherein it dissolves to form a solution which is useful for cleansing articles such as artificial dentures by immersion therein. As used herein, the term cleansing jointly encompasses cleaning, bleaching, destroying or retarding growth of microorganisms, deodorizing, and the removal of particulate matter.

Also as used herein, the term denture includes artificial teeth, removable orthodontic bridges and denture plates. Such dentures are usually constructed of porcelain or plastics such as phenolformaldehyde, acrylic and cellulose acetate resins, and metals such as alloys of chromium and cobalt.

A very important property sought in a denture cleanser is a high degree of overall cleaning including the removal of films, particles and debris. Another important property is the capacity to remove stains caused by substances such as coffee, tea or tobacco smoke without harming the porcelain, plastics or metals of the dentures. A further desirable property is the ability to destroy or retard the growth of microorganisms.

Numerous types of cleansers for artificial dentures have heretofore been suggested and marketed but none of them have been found to be entirely satisfactory.

For example, certain of the cleansers of the prior art are acidic, that is, they utilize a pH of about 7 or less in order to achieve sufficient cleansing. However, such acidity exerts a corrosive or otherwise adverse effect upon metals or other portions of the dentures.

On the other hand, another series of cleansers depend upon a relatively high degree of alkalinity to produce a cleansing action. Of course, a high degree of alkalinity, for example, a pH of about 12 or more can cause damage to denture structures and in addition results in a product which is not convenient to use.

In any event, previously known denture cleansers generally fall into two main classes: the immersion type designed specifically for complete submersion of the denture in the cleansing solution; and, the paste or powder type cleanser which is mechanically applied. With immersion cleansers, the denture is soaked in a solution provided by dissolving a powder or tablet in warm water after which it is removed, rinsed and returned to the mouth. Such cleansers, if they are to provide a sufficient degree of cleansing, often require an undesirable high or low pH as noted above. In addition, the simple immersion cleansers are often deficient in removing particulate matter, for example, food debris, which adheres to the surface and which is found in the crevices of the denture. In regard to the paste or powder type cleansers, adequate cleansing can be achieved by mechanical action, for example, brushing, but this creates the risk of dulling the otherwise smooth polished surfaces of the denture which in turn allows a more rapid redeposition of tartar and subsequent stainmg.

The art has provided partial solutions to these denture cleansing problems. One step in the right direction has been the provision of effervescent formulations in the form of powders or tablets which dissolve and release an effervescent gas such as carbon dioxide or oxygen. The gas bubbles, as they pass the denture, contribute a gentle mechanical cleaning action and thus help to remove particulate matter. In addition, when oxygen contacts the denture, it tends to remove stains thereon and provide antiseptic action.

As just indicated, denture cleansing compositions can be prepared in the form of powders and this is highly desirable because of the convenient handling characteristics possessed by these powders. Such powders can be packaged in unit quantities to obviate the need for measuring or the powders can be packaged in bulk so that the user can control the strength of the cleansing solution.

However, in formulating denture cleanser powders which effervesce oxygen severe problems have heretofore been encountered.

In particular, it has been difficult to formulate such a powder which has sufficient stability to withstand normal packaging and storage and yet which dissolves rapidly to effervesce oxygen when placed in water.

Moreover, in the case of oxygen releasing powders, it has been found desirable to utilize a relatively high pH to provide a media in which oxygen is relatively insoluble so that the oxygen bubbles will effervesce at a rapid rate to obtain a mechanical type cleansing action as these bubbles pass the denture. However, too high a pH, for example, greater than about 12, should be avoided for safety reasons and to prevent excessive effervescence.

In addition, activators which have been used to trigger release of oxygen from oxygen precursors such as perborates, persulfates or peroxides, as well as lubricants or diluents, often result in hazy or cloudy solutions or contribute an objectionable odor. A clear solution is highly desirable from the standpoint of avoiding the redeposition of any materials which would contribute toward a dulling film, and a pleasant odor is, of course, desirable for cleansing products.

Still other prior art formulations tend to foam during use which can cause spillage and obscure visual examination of the cleansing progress.

SUMMARY OF THE INVENTION In view of the need in the art as just described, the present invention provides a stable cleansing powder which when added to water dissolves at a favorable rate to fonn a clear, non-foamy, oxygen-effervescent solution of pH 10.5 to 11.8. This powder is stable, yet it readily dissolves in 2 to 40 minutes when placed in water. The composition of the invention which achieves these desirable results comprises: 20-50 percent sodium perborate monohydrate; 40-60% lithium hypochlorite; and 5-25 percent phosphate salts.

Another novel contribution to this art can be found in the commonly assigned application of Michael Brown and Jean Breece on Effervescent Tablet, application Ser. No. 165,394, filed concurrently herewith.

DETAILED DESCRIPTION A detailed listing of the cleanser compositions of the present invention is set forth in Table I.

TABLE 1 CLEANSER COMPOSITION Broad Preferred Most Composition Composition Preferred Composition Ingredient by weight) by weight) by weight) Sodium Perborate 20-50 25-35 30-33 Monohydrate Lithium 40-65 50-60 53-56 Hypochlorite Phosphate Salts 5-25 -20 12-15 (total) Sodium 10-20 14 Tripolyphosphate 5-25 Sodium Hexametaphosphate 5-25 Trisodium 5-25 Phosphate pH 10.5-11.8 10.8-11.5 11.2-11.4

It has been discovered as a part of this invention that the composition and proportions of ingredients of Table 1 provide an extremely effective and convenient effervescent denture cleanser. Each of these ingredients cooperate with the others in the control of oxygen generation and effervescence, pH, and/or cleansing.

Thus, compositions of Table I possess the following characteristics:

When such composition is placed in water, for example, 20 to 40 parts of water at about 35 C. to 45 C., it readily dissolves without agitation in 2 to 40, preferably 5 to 20 minutes to form a clear, non-foamy solution having a pH within the ranges indicated.

In aqueous solution within this pH range, the lithium hypochlorite compound releases available hypochlorite which provides a known antiseptic effect. More importantly, the hypochlorite reacts with the sodium perborate monohydrate and activates its release of free oxygen into the system.

Also within the pH ranges indicated, oxygen has a low degree of solubility in aqueous solutions and thus the oxygen released to the solution by the sodium perborate monohydrate compound naturally effervesces. The composition is so balanced that the effervescence commences immediately upon contact with water and continues at a desirable rate for a period of from 5 to 60 minutes, preferably 15 to 25 minutes. ln addition, the composition is such that the oxygen is released in the form of small bubbles. This is desirable since large bubbles could tend to lift the denture out of the cleansing solution.

Such effervescence of small oxygen bubbles insures intimate contact of oxygen with the surface and crevices of the denture to provide a high level of stain removal therefrom. Further, the small bubbles effervesce at a rate sufficient to provide a mechanical or scrubbing" action as they pass the denture and thus physically assist in the removal of particulate matter.

It is to be noted that the proportion (on a mole basis) of sodium perborate monohydrate compound to lithium hypochlorite compound is such that substantially complete consumption of hypohalite is realized prior to cessation of effervescence thereby avoiding undue release of free chlorine from the solution with its accompanying objectionable odor. In other words, there is an excess of perborate to hypohalite to insure that the solution has oxidizing power and that free chlorine is not released.

With further reference to Table I and the ingredients listed therein, the sodium perborate monohydrate has the empirical formula NaBO -,'H O and is commercially available as a dry granular or powder material. Although other oxygen precursors including other perborates are available in the art, the specific selection of sodium perborate monohydrate in this invention is important to achieve the desired rate and type of oxygen effervescence as well as powder dissolution. However, minor amounts of anhydrous sodium perborate or sodium perborate tetrahydrate can be used in conjunction with the sodium perborate monohydrate.

Lithium hypochlorite, LiOCl, is also commercially available in granular form. More specifically this material is available as a dry, stable granular composition having the following typical analysis:

The above-identified composition contains about 35 percent available chlorine. As used herein and the accompanying claims, the term lithium hypochlorite refers to such compositions which contain about 30 percent LiOCl and 35 percent available chlorine. Processes for preparing these lithium hypochlorite compositions are found in US. Pat. Nos. 2,590,794 and 2,534,- 781.

Although other hypochlorite salts are available, for example, sodium, potassium, calcium and magnesium hypochlorite, it has been discovered that lithium hypochlorite is unique for use herein. Thus, sodium and potassium hypochlorite cannot be obtained in a stable dry form. Calcium and magnesium hypochlorite, though stable in any form, are not sufficiently water soluble. Lithium hypochlorite, as noted above, can be prepared in a dry, stable form and when used in the composition of this invention, it readily dissolves in water to provide available hypochlorite and a very clear solution.

The composition contains 5 to 25 percent phosphate salts. Illustrative of useful salts are tribasic phosphates, orthophosphates, tripolyphosphates, hexametaphosphates, pyrophosphates and the like. Suitable cations in these phosphate salts are sodium, potassium, ammonium, calcium, magnesium and the like.

As noted in Table 1, preferred phosphate salts are sodium tripolyphosphate, trisodium phosphate and sodium hexameta-phosphate. Of these, sodium tripolyphosphate is especially preferred, particularly in its anhydrous form. This particular phosphate salt has been found to provide the effervescent composition of this invention with outstanding denture cleansing properties. This ingredient is commercially available in granular or powder form.

Other than the usual adjuvants such as minor amounts of dyes, perfume and the like, the compositions of this invention are preferably limited to the ingredients of Table 1. However, if desired, other ingredients normally used in cleaning compositions can be included. Examples of such ingredients are surfactants such as soaps or synthetic detergents, sequestrants such as salts of ethylenediamine tetraacetic acid (EDTA) or nitrilotriacetic acid (NTA), and builders and/or fillers such as sodium silicate, sodium chloride, or sodium sulfate.

In use, the powder is preferably placed in to 60 parts, most preferably to 40 parts of water at 20 C. to 60 C., preferably 35 C. to 45 C. and allowed to dissolve, for example, in the presence of the denture, without stirring or other agitation.

After a suitable period of time, for example, 3 minutes to 60 minutes, preferably 5 minutes to 20 minutes, the dentures can be removed from the solution and readily rinsed. These dentures will be physically and bacteriologically clean. In addition, they will have a desirable clean taste and clean feel.

Conventional methods can be employed to produce the compositions of this invention in ready to use powder form. For example, the ingredients can be dry blended, segregated into unit-size portions, and then packaged, preferably in moisture-proof wrappings. A particle size reduction step can be utilized, if desired, before or after the blending.

The composition in powder form can have a bulk density of 0.2 to 1.5 grams/cc, preferably 0.5 to 1.0 grams/cc. Suitable unit-size portions can weigh from one gram to grams or more, preferably from 3 grams to 10 grams.

Preferably the powder compositions of the invention have a particle size distribution of: 100 to 95 percent through 14 mesh and l to 5 percent through 100 mesh U.S. Std. Sieves.

All precentages, parts and proportions herein are by weight unless specifically stated otherwise. All references to pH are based on a 2.5 percent aqueous solution.

EXAMPLE I A powder composition was prepared by dry blending the ingredients of Table II.

TABLE II INGREDIENTS IN EXAMPLE I POWDER COMPOSITION Ingredient Percent by Weight Sodium perborate monohydrate 31.0 Lithium hypochlorite 54.5 Sodium tripolyphosphate, anhydrous 14.3 dye, perfume or flavor balance Obtained from Lithium Corporation of America under the tradename Lithcoa and having the following typical analysis:

This powder was stable when subjected to normal handling, packaging and shipment. When 5 grams of the powder was placed in 150 grams of 40 C. water,

the powderdissolved in 3 to 5 minutes without agitation to form a clear, non-foamy solution'of pH 11.3. Immediately upon placement of the powder in the water, small bubbles of oxygen effervesced at a rapid rate and this effervescence continued for about 60 minutes.

In order to evaluate the denture cleansing properties of the powder of Example I, an artificial soil consisting of lamp black dispersed in a mixture of hydrogenated vegetable oil and a liquid fatty acid, and known to cause staining of dentures was prepared and smeared in the marginal and cervical areas of test sections of a denture. These test pieces were then conditioned for 18 hours at 104 F. The treated dentures were placed in separate beakers each containing 150 ml water, one at 68 F. and the other at 1 13 F. About 5 grams of powder was then placed into each beaker with subsequent effervescence. The dentures were allowed to remain for 12 minutes in the 113 F. water and 15 minutes in the 68 F. water and then removed. After rinsing, the dentures were visually checked for degree of soil removal. The test pieces rinsed free of all soil and were clean. In comparison, pieces treated in the same manner as just described using one of the leading commercially available cleanser powders required additional brushing to remove all traces of soil.

Concentrates of coffee and tea were prepared and individual sections of denture were allowed to soak in these solutions until a stain developed. These test sections were then conditioned for 18 hours at 104 F. Once again, 5 grams of powder was placed into each of 4 beakers in two sets each containing 150 cc of water at either 68 F. or 113 F. The stained sections were placed in the cleansing solution for 3 to 5 minutes at which time visual observations indicated them to be clean. They were then rinsed and examined closely. In all instances they were free of stain and clean in appearance. A comparable evaluation using one of the leading commercially available cleanser powders was once again made. The comparison powder was less efficient at removing these stains in a comparable period.

Sections of a denture teeth and gum surfaces were exposed to cigarette smoke from a given number of cigarettes in a closed vessel over a period of several minutes allowing for a substantial film of tar and nicotine to be deposited on the exposed surfaces. A conditioning period of 18 hours at 104 F. followed this staining procedure. The stained sections were cleansed as above. Having soaked in the cleansing solution for either 40 minutes at 68 F. or 4 minutes at 113 F. at which times a preliminary check indicated them to be clean, they were then removed and rinsed. In all instances, the pieces which had been immersed in the solution were totally cleansed. Similar sections immersed in a solution from one of the leading commercially available cleanser powders were less efficiently cleansed even after 30 minutes exposure at 68 F. or 1 13 F.

The anti-bacterial activity of the cleanser powder of this Example was evaluated in the following manner. 5 grams of the powder was dissolved in cc warm water and after effervescing for 5 minutes the solutions were inoculated respectively with standardized suspension of Escherichia coli, Pseudomonas aeruginosa, Micrococcus pyogenes var. aureus, Streptococcus pyogenes, and Candida albicans organisms (pertinent to the oral flora of the mouth or infection). It is to be noted that both gram positive and gram negative organisms were used. The microorganisms tested were completely killed when exposed for a 10 to minutes contact period.

The following powders of Table II are prepared in accordance with Example I and will perform in an equivalent manner.

Although described herein in terms of its primary utility as a denture cleanser, it is apparent that the composition of this invention can be otherwise used. For example, the composition is useful for cleansing dishes, sinks, toilet bowls and the like. Also, although the cleanser composition has primarily been described herein as being in powder form, which is a preferred embodiment, it is apparent that other physical forms can also be prepared and utilized. For example, the powder composition can be compressed into a tablet according to methods well known in the art.

As used herein, the term non-foamy refers to a substantial absence of foam but does not mean an absolute absence of foam since the desired effervescence does, of course, result in a minor accumulation of bubbles on the liquid surface.

What is claimed is:

1. A stable denture cleansing composition which when added to water dissolves in 2 to 40 minutes to form a clear, non-foamy, oxygen-effervescent solution of pH 10.5 to 1l.8 said composition consisting essentially of:

20-50 percent Sodium perborate monohydrate -60 percent Lithium hypochlorite 5-25 percent Phosphate salts selected from the group consisting of the sodium, potassium and ammonium, tribasic phosphates, orthophosphates, tripolyphosphates, hexametaphosphates, pyrophosphates or polyphosphonates.

2. The composition of claim 1 wherein the oxygeneffervescent solution effervesces oxygen for a period of 5 to 60 minutes.

3. The composition of claim 1 which consists essentially of:

25-35 percent sodium perborate monohydrate -60 percent lithium hypochlorite 5-25 percent phosphate salts selected from the group consisting of sodium tripolyphosphate, trisodium phosphate and sodium hexametaphosphate.

4. The composition of claim 3 wherein the phosphate salt is sodium tripolyphosphate.

5. The composition of claim 3 wherein the phosphate salt is trisodium phosphate.

6. The composition of claim 3 wherein the phosphate salt is sodium hexametaphosphate.

7. The composition of claim 4 which dissolves to form a solution of pH of 108-1 1.5 based on a 2.5 percent aqueous solution.

8. The composition of claim 4 which consists essentially of:

30-33 percent sodium perborate monohydrate 53-56 percent lithium hypochlorite 12-15 percent sodium tripolyphosphate 9. The composition of claim 4 wherein the sodium tripolyphosphate is in its anhydrous form.

10. The composition of claim 8 which dissolves to form a solution of pH of about 11.2-11.4 based on a 2.5 percent aqueous solution. 

2. The composition of claim 1 wherein the oxygen-effervescent solution effervesces oxygen for a period of 5 to 60 minutes.
 3. The composition of claim 1 which consists essentially of: 25-35 percent sodium perborate monohydrate 50-60 percent lithium hypochlorite 5-25 percent phosphate salts selected from the group consisting of sodium tripolyphosphate, trisodium phosphate and sodium hexametaphosphate.
 4. The composition of claim 3 wherein the phosphate salt is sodium tripolyphosphate.
 5. The composition of claim 3 wherein the phosphate salt is trisodium phosphate.
 6. The composition of claim 3 wherein the phosphate salt is sodium hexametaphosphate.
 7. The composition of claim 4 which dissolves to form a solution of pH of 10.8-11.5 based on a 2.5 percent aqueous solution.
 8. The composition of claim 4 which consists essentially of: 30-33 percent sodium perborate monohydrate 53-56 percent lithium hypochlorite 12-15 percent sodium tripolyphosphate
 9. The composition of claim 4 wherein the sodium tripolyphosphate is in its anhydrous form.
 10. The composition of claim 8 which dissolves to form a solution of pH of about 11.2-11.4 baseD on a 2.5 percent aqueous solution. 